Power supply for radio receiving sets



Oct. 29, 1940. D, Q lsRAEL E1- AL 2,220,051

POWER SUPPLY FOR RADIO RECEIVING sETs Filed Oct. 31, 1939 Nba Dorman D. Israel Louis F. Wil/ging Patented Oct. 29, 1940 UNITED STATES PATENT OFFICE POWER SUPPLY FgtgADlO RECEIVING Application October 31, 1939, Serial No. 302,104

16 Claims.

This invention is concerned with the pOwer supply of a radio receiving set of the type adapted for operation from the power supplymeans of either alternating current or direct current characteristics or for operation from batteries.

The general object of this invention is the provision of a circuit for a multi-tube radio receiving set including the power supply connections arranged so that the set user by the simple manipulation of the plug-in connector may connect the set to either an alternating current or a direct current power supply outlet for operation therefrom or to a receptacle incorporated in the set for operation from batteries which normally would be enclosed within the receiver casmg.

A more specific object of the invention is the provision of apparatus of the above type by means of which it is impossible to operate the set simultaneously from the power supply source and from the batteries.

Another object of the invention is the provision of a receptacle incorporated in the receiving set and a plug connector for cooperation therewith whereby the connector may not be mounted in the receptacle in any other than the correct way, but it may be applied to any standard power outlet receptacle either way.

Ay still further object of the invention is the provision in a receiving set of the above type of means for equalizing the flow of plate current through the various vacuum tube iilaments to ensure against premature deterioration of the iilaments. 5 A still further object .of the invention is the provision of circuit arrangements whereby when the receiving set as above referred to is operating from batteries the rectifier vacuum tube and the power supply output tube do not have their heaters energized for operating and when operating from thepower circuit the battery output tube does not have its filament energized.

These as well as other objects will be fully apparent from the following detailed description of the speciiication when taken in connection with the attached drawing.

This invention resides substantially in the combination, construction, arrangement, and relative location of parts, all in accordance with this disclosure. i

In the accompanying drawing, the single ngure is a diagrammatic illustration of the circuit arrangements of one form of the invention showing diagrammatically only the parts with which this invention is concerned.

It is a fairly frequent practice at the present time to provide radio receiving sets which are capable of operation without manual manipulation from ordinary house lighting power supply circuits whether of alternating current or direct current characteristics and in addition upon simple adjustment for operation from batteries. Several different types of manipulative structures have been provided to effect this changeover and the present invention is concerned with an improved and simplified arrangement by means of which radio receiving sets equipped therewith may be quickly prepared, without danger of improper connection, for operation either from house lightingv circuits or batteries.

There is illustrated in the single figure of the drawings the filaments I, 2, 3 and 4 of what may be -termed'the preliminary tubes of an ordinary radio receiving set or other electronic amplifier apparatus. As will be apparent to those skilled in the art, the invention may be applied to many different forms of radio receiving sets. For example, the filaments I, 2 and 3 may be considered to be the filaments of the radio frequency amplifier tubes, while the lament 4 is the filament of a vacuum tube detector. For purposes of description and in accordance with common practice, it will be assumed that each of these filaments requires 0.05 ampere for its operation and a voltage of 1.4 volts. It is, of course, apparent that these values are not critical and that tubes of other power requirements may be employed. At 5 is diagrammatically shown the filament of a battery type of output audio frequency amplifier tube which operates on a. voltage of 2.8 volts and an amperage of 0.05 ampere. These operating characteristics are likewise not critical.

All five of these filaments are shown connectcd in series with one current supply lead 6 connected to a wire 1 of the power supply cord which terminates in a plug i0 having terminal prongs 9 and 33. Wire 'i is connected to the terminal prong 9 and grounded as indicated at 8. This ground represents the usual common negative return connection of the receiver. The 4 other terminal of these filaments in series is connected by wire Il to the positive side of the A" battery I2. The negative side of this battery is connected to a contact finger I4 in the plug receptacle incorporated in the set and described in greater detail later. As will be apparent to those familiar with this subject matter, the invention is not limited to use in circuit arrangements employing filaments in series, since parallel and series parallel filament arrangements can be As a resultl the contactprong 33 must always The filaments I, 2, 3 and 4 are shunted by resistances I5, I6, I1 and I8, the use and function of which are well known in this art.

The vacuum tube rectifier is diagrammatically illustrated as of the indirectly heated type having a heater I9, a cathode 24, and an anode 3|. One terminal of the heater I9 is connected by wire 26 to the grounded lead 1. The indirectly heated cathode 24 is connected through a low frequency choke coil 25 to wire' 26 which connects to one terminal of the primary winding 30 of the audio frequency output transformer of the receiver. The other terminal of this winding is connected by wire 28 to the anode 29 of the battery type audio frequency output tube. The anode 3i of the rectifier tube is connected by wire 32 to the contact prong 33 of the plug connector I0.

Wire 32 is connected by Wire 34 to one terminal of the heater 35 of the light socket output tube. This heater 35 by means of wire 36 is connected in series with the heater I9 of the rectifier tube. The indirectly heated cathode 31 of the power output tube is connected by wire 38 to one terminal of the filament 4, as shown, and by wire 39 to a resistance 40, which in turn is connected to the contact finger 4I of the plug receptacle. The other contact 42 of the pair including the contact 4I serves no useful electrical function in the arrangement illustrated. The other contact 43 of the pair which includes the contact I4 is connected by wire 44 to the negative terminal of the B battery 45. The positive terminal of this battery is connected by wire 46 to a wire 41. The

wire 41 is connected to wire 26 which is the positive output terminal of the filter which includes the low frequency choke coil 25 and the capacitors 10 shunted across the output of the rectifier.

liOfIn a completed circuit the Wire 41 would extend fier tube. The control grid 5I of the battery output tube is connected to wire 22. The grid 49 of this tube is connected by wire 50 to the terminal of the primary winding 30, to which wire 26 is connected. The grid 48 is connected to the mid- 50 point of the filament 5. In the power output tube the control grid 56 is connected by wire 51 to wire 22, the grid is connected to the wire 26, while the grid 54 is connected to wire[38. The output electrode 53 of the power output tube is connected 55 by wire 52 to a tap point on the primary 36.

The secondary 62 of the audio frequency output transformer is adapted to be connected to the loudspeaker, which is not shown.

The plug receptacle, of which contacts I4, 4I, 42 and 43 are a part, may assume any one of a number of physical forms and, therefore, has been diagrammatically illustrated. As shown, it includes a plate or base 59 which has a pair of slots 58 positioned with respect to the contacts so that when the contact prongs 9 and 33 of the plug ID are inserted through these slots certain connections are made. Mounted on the base 59 in the proper position is lan obstruction or dam 60, the position of which is such that the plug I0 may only be mounted in the receptacle in a single and correct way. As shown, the plug I0 is constructed with a wing 6I so that the plug connector I0 may only be applied to the receptacle so that the contact prong 9 enters the slot 58 with which the contacts I4 and 43 are associated.

enter the slot 58 with which the contacts 4| and 42 are associated. However, the wing 6I of plug I0 does not interfere with the application of the plug to the usual power outlet receptacle in either direction. f

For battery operation the plug I0 is inserted in the receptacle 59 so that the negative terminals of the A" and B batteries are grounded through the contacts I4 and 43, the contact prong 9 which engages them, and ground 8 by Way of wire 1. The result is that the laments I, 2, 3, 4 and 6 are energized'as follows:

Current iiows from the positive side of the A" batt/ery I2 through wire I I, filaments 5, 4, 3, 2 and I, wire 6, wire 1, contact prong 9, contact I4, and wire I3 back to the negative side of the A battery I2. Thus these filaments are energized in series. The B battery is connected between the plate electrodes of the various tubes and ground through wires 41 and 46, B battery 45, wire 44, contact 43, contact prong 9, wire 1, to the grounded side of the filament system. The positive terminal of the B battery is also connected from wire 41, through wire 26, primary 30 and wire 28 to the plate electrode 29 of the battery output tube. At this time it will be seen that the heaters I9 and 35 are not energized. Thus they perform no function in so far as the signal operationv is concerned. However, it will be seen that they are connected in series with the resistance 40 to provide with them a shunt across the laments I, 2, 3 and 4. The shunt circuit includes wires 6, 1 and 20, heater I9, wire 36, heater 35, wire 34, wire 32, contact prong 33, contact 4I, resistance 40, and wire 39 to the other side of the circuit, comprising the filaments I, 2, 3 `and 4 in series. The function of this circuit is to equalize the ow of current through these laments automatically for both power supply and battery operation, as explained below.

It is well known that with the open filament types of tubes, that is, the type in which the filament acts as the cathode, when a number of them are connected in series, the most negative filament must carry not only its own energizing current but the combined plate currents of all the other tubes. The other filaments are likewise subjected to the flow of plate current from the subsequent tubes but to a progressively less degree. It is normally possible to place shunt resistors across the iilaments of these tubes using the lowest resistance across filament I and progressively higher resistances across the filaments 2, 3 and 4. However, in the arrangement disclosed, the battery output tube 5 draws the heaviest plate current so that the iilaments I, 2, 3 and 4 must carry this output tube plate current during battery operation. The shunting effect of resistances I5, I6, I1 and I8 is not satisfactory, therefore, for battery operation because the plate current of the battery output tube overloads the iilaments I, 2, 3 and 4.

Therefore, in accordance with this invention, to get perfect equalization of the filament current during battery operation the iilaments I, 2, 3 and 4 are shunted by resistances I5, I6, I1 and I 8, respectively, properly proportioned for light socket operation, and resistance 40 is connected as shown so that when the plug I0 is placed in the receptacle 59 the additional current resulting from the operation of the battery output tube is shunted through it and the cold inoperative heaters I9 and 35. This additional resistance just equalizes the overload imposed by the battery serted in a conventional power outlet socket in the usual way. At this time, the heaters I and are rconnected across the line in-series and the rectifier and light Asocket, output tubes are energized for operation either from direct or alternating current. l'lhe output terminals lof the filter for the rectifier are connected as described before to supply the proper anode potentials. In the example being described. the light socket output tube is so chosen that its cathode current is 0.05 ampere, which current ows through the filaments l, 2, 3 and I, thereby energizing them. It should be noted that while energy is then supplied to the filaments I, I, I and 4 in series, no current is supplied to filament i. Removal of plug Il) from the receptacle N has cut the filament 5 out of the circuit and simultaneously broken the circuits to the A" and B" batteries so that they are not functioning at thistime.

A practical advantage of a system of this type is demonstrated by the use of a battery outputy tube of lower power -requirements during battery operation thus conserving the batteries. In power operation an output tube of higher power requirements and output is used giving-better performance as for example l watt output as compared with 0.2 watt outputMfor the battery operated output tube.

From the above description it will be apparent to those skilled in the art that we have provided in a simple and foolproof form a circuit arrangement and control elements therefor which may not befmanipulated in -any way by the uninformed to the damage of the set or any of the parts thereof. We are, of course, aware that 40 the objects of this invention may be accomplished in other ways and with structurally different elements. and we do not. therefore, desire to be strictly limited -to the disclosure as given for the purpose of illustrating our invention,

but rather to the scope of the claims granted What is claimed is:

1. In radio apparatus, the combination including a multi-stage vacuum tube amplifier, each tube including at least a cathode and an anode, circuit means for supplying energizing currents for said cathodes and operating potentials for said anodes from either a direct or an alternating current power source or from a battery source, including a' single plug receptacle, and circuit completing means including a single plug connector for attachmentv to either a direct or an alternating current power source or to said plug receptacle to energize the circuit means from the battery source.

2. In radio apparatus as described. a vacuum tube amplifier, each vacuum tube thereof having at least a cathode and an anode, means including a vacuum tube rectifier for supplying energizing current to said cathodes and operating potentials to said anodes from either a direct or alternating current house lighting circuit, a battery source, normally open circuit means for supplying energizing current to said cathodes and operating potentials to said anodes from said battery .source when closed, and circuit completing means including a single plug connector for connecting said rst means to a house lighting circuit or for closing said normally open circuit means. v

resistance rIl is no s 3. In a vacuum tube operated radi'receiver, a' plurality of cathodes connected for seriesenergization, anodes associated respectively with said cathodes, a vacuum tube rectifier, circuits connecting said rectifier for supplinsr said cathodes with energizing current and said anodes with operating potentials, means including a plug connector for supplying electrical energy to said rectifier from either a direct or alternating current power source, a battery power source, a resistor, and means including a switching device operated by the insertion of said plug connector for supplying energizing current to said cathodes and operating potentials to said anodes from said battery source and for connecting said resistor in shunt with said cathodes in series.

4. In a vacuum tube operated radio receiver,- a plurality of cathodes connected for series energization, anodes associated respectively with said cathodes, a vacuum tube rectifier, circuits connecting said rectifier for supplying said nlaments with energizing current and saidanodes with operating potentials, means including a plug connector for supplying electrical energy to said rectifier from either a direct or alternating current power source, a battery power source, means including a switching circuit operated by said plug connector for supplying energizing current to said cathodes and operating potentials to said anoles'from said battery source, and means for ensuring the application of said plug connector to said switching device to correctly polarize the circuits when operated from said battery source. 5. In a vacuum tubeoperated radioreceiver, a

.plurality of cathodes connected for energization,

anodes associated respectively with said cathods, a vacuumtube rectifier, circuits connecting said rectifier for supplying said cathodes with energizing current and said anodes with operating potentials, means including a single plug connector for supplying electrical energy to said rectifier from either a direct or alternating current power source, a battery power source, and means including a switching device operated by the insertion of said plug. connector for supplying energizing current to said cathodes and operating potentials tol said anodes from said battery source, said battery source being disconnected from the circuits at said switching device when said plug connector is removed therefrom.

6. -An electronic amplifier using several vacuum tubes, each vacuum tube having a cathode and an anode, a vacuum tube rectifier, circuits for energizingsaid cathodes from said rectifier and for supplying operating potentials to said anodes. means including a single plug connector for supplying electrical energy to said rectifier from either a direct or alternating current house lighting circuit, a battery source, and switching circuits including a plug receptacle for energizing said cathode from the battery source and supplying operating potentials to said anodes, said switching device being operated by the application of said plug connector to said receptacle.

7. In a radio receiving set,` a multi-stage vacuum tube amplifier, each vacuum tube thereof having a cathode and an anode, a vacuum tube rectifier, circuits for energizing said cathodes in series from said rectifier and for supplying operating potentials to said anodes, means including a plug connector for supplying electrical energy to said rectifier from either a direct or alternating current house light circuit.. battery sources, and circuits including said battery sources .and contact fingers for energizing said cathodes in series from the battery source and supplying operating potentials to said anodes 5 upon engagement of said plug connector with said contact iingers, said battery source circuits being broken at said contact ngers upon disengagement of the plug connector.

8. In a multi-stage vacuum tube operated amplier, each vacuum tube thereof having a cathode and an anode, a vacuum tube rectifier, circuits for energizing said cathodes in series from said rectifier and for supplying operating p'otentials to said anodes, means including a plug connector for supplying electrical energy to said rectiiier from either a direct or alternating current house lighting circuit, a battery source, a contact plug receptacle, circuits including said battery source and the contacts of 'said receptacle for energizing said cathodes in series from the battery source and supplying operating potentials to said anodes, said battery circuits being completed by the engagement of said plug connector with said contacts, and means for ensuring the application of the plug connector to the switching device to correctly polarize the battery circuits. v

9. In a radio circuit, a multi-stage vacuum tube ampliiier, a first power output vacuum tube, each of said vacuum tubes having an open i'llamentary cathode, the vacuum tube rectiiier having a heater, a second power output vacum tube having a heater, circuits for energizing the cathodes of the amplifier vacuum tubes `from said rectifier and the heater of said second power output tube, means including a plug connector for energizing said circuits from a direct or alternating current house lighting cireuit,'a battery current source, circuits including said battery 0j source for energizing the cathodes of said amplier and-first power output tube, and means in said last circuits for completing them upon the application thereto of said plug connector.

10. In an amplifier circuit, a multi-stage'vac- 45 uum tube ampliiier, a rst output vacuum tube,

each of the vacuum tubes having an open lamentary cathode and an anode, a vacuum tube rectifier having a heater, a secondI output vacuum tube having a heater, circuit for energizing 50, the llamentary cathodes of the amplifier-vacuum tubes in series from said rectiiier and for supplying operating potentials to said anodes, means including a plug connector for energizing the heaters of said receiiierand second out- 55 put tube in series from a direct or alternating current house lighting circuit, a battery current source, a switching device, circuits including said battery source, switching device and the lamentary cathodes of the ampliiier, and the rst A60 output tube in series, said switching device being operated to complete the battery circuits upon application to said switching device of said plug connector, resistances shunting the lamentary cathodes of the amplifier tubesl and a shunt re- 65 sistance circuit fo'r the lamentary cathodes of the ampliiier tubes completed byA the application of the plug lconnector to the switching device.

11. In an amplifier circuit, a multi-stage vacuum tube ampliiier, a first output vacuum tube,

70 each of said vacuum tubes having an open mamentary cathode, Aa rectiiier -tube having a heater, a second output vacuum tube having a heater, circuits for energizing the cathodes of the amplifier vacuum tubes in series from said recti- 75 iler, means' including a plug connector for energizing the heaters of said rectifier andv second output tube in series from a direct or alternating current house lighting circuit, a battery current source, a switching device, circuits including said battery source, switching device and the iila- 5 mentary cathodes of the ampliiier and the first output tube in series. said switching devicebeing operated to complete the battery circuits upon application to said switching device of said plug connector, means for shunting the iilamentary cathodes of the amplifier tubes individually, and a shunt resistance circuit for the iilamentary cathodes of the ampliiier tubes as a unit, completed by the application of the plug connector to the switchingdevice, said last shunt circuit including the heaters of said rectiiier and second output tube.

12.- In a circuit of the type described, a vacuum tube rectiiier, a plurality of iilamentary cathodes connected in series to the output of said rectiiier, means including a plug connector for energizing said rectiiier from a direct or alternating current house lighting circuit, a battery current source,` and switching circuits including said battery current source for operating said-lilamentary cathodes in series from said battery upon completion of said switching circuits by said plug connector,

\ 13. In a radio receiving set, a vacuum tube rec' tiiier, a plurality of lamentary cathodes connected in series' to the output of said rectiiier, means including a plug connector for energizing said rectiiier from a direct or alternating current house lighting circuit, a battery current source, a switching device operable by said plug connector, circuits including said battery current source I and switching device for operatingy said iilamentary cathodes in series when said plug connector operates said switching device. and a shunt circuit including resistances across all of said lamentary cathodes, said shunt circuit being completed upon the operation of the switching device by said plug connector.

14. In a radio receiving set, a vacuum ,tube rectiiier, a plurality of iilamentary cathodes connected to the output of said rectiiier, means including a plug connector-'tor energizing said recltiiier from a direct or alternating current 'house lighting circuit, al battery current source, a switching device operable by said plug connector, circuits including said battery current source and switching device for operating said lamentary cathodes from said battery when said plug connector operates said switching device, and a shunt circuit including resistance across all of said iilamenary cathodes, said shunt circuit being completed upon the operation of the switchingdevice by said plug connector.l

15. In a radio circuit, the combination including a vacuum tube rectiiier having va. heater, an output tube having a heater, a plurality of niamentary cathodes connected in series to the output of said rectiiier, means including a plugconnector for energizing the heaters of said rectiiier yand output tube in series from either a' direct or alternating current house lighting circuit, a'second output tube having a filamentary cathode, a

, battery current source, a control device, and

circuits including said battery current source and control device for connecting certain of said iila- 70 mentary'cathodes in series to the battery current source when the control device is operated by said plug connector.

16. In radio apparatus, the combination including a vacuum tube rectifier having a heater,

an output tube having a heater, a plurality of iilamentary cathodes connected in series to the output of said rectier, means including a plug connector for energizing the heaters of said rectifier and output tube from either a direct or a1- ternating current house lighting circuit, a second output tube having a i'llamentary cathode, a battery current source, a control device, and circuits including said battery current source and control device for connecting all of said lamentary cathodes in series to the battery current source when the control device is operated by said plug connector, resistances individually shunted across all of said filamentary cathodes with the exception of the cathode of the second output tube, and a shunt circuit connected across the same tllamentary cathodes as a unit including the heaters of said rectiiier and rst power output tube, said shunt circuit being completed when said control device is operated by said plug connector.

DORMAN D. ISRAEL. LOUIS F. WELGING. 

